In the field of electrical lighting, LED (light emitting diode) elements are increasingly used due to their advantageous properties of high efficiency and long lifetime. Also, LEDs are already used for automotive lighting, including both automotive signalling lamps and automotive front lighting.
Important aspects in the design of an LED lighting unit comprise mechanical, electrical, optical, and thermal design. In terms of mechanical design, an LED lighting unit should have the necessary stability and fulfill dimensional requirements. According to electrical design aspects, the LED lighting unit should be compatible with and connectable to a given source of electrical power. Optical design requires sufficient luminous flux generated from LED elements and a spatial distribution of the luminous flux as required for the specific lighting task. Finally, thermal design requires that heat generated from operation of the LED elements is dissipated to maintain stable thermal operating conditions.
US 2011-0050101 describes a lighting system including a replaceable illumination module coupled to a base module. The illumination module comprises solid state lighting elements, such as LEDs, and a heat sink in thermal contact, which may have a plurality of heat fins. The heat sink may comprise a plurality of stacked extrusions with such heat fins, each having a respective radius, to form a stepwise tapered heat sink. In a preferred embodiment, the illumination module has a base connector to receive power from a lighting socket, and a driver circuit to receive power from the base connector and provide electrical power to the solid state lighting element on a printed circuit board.